Foldable articulated arm

Abstract

It is described a foldable articulated arm comprising a first rod-shaped element, a second rod-shaped element and a third rod-shaped element foldable one another and at least three stretching element of the rod-shaped elements, arranged to form a system of four-bar linkages, further comprising a plurality of joint elements of the rod-shaped elements and the stretching elements and having, at the opposite ends, a retaining mechanism for a respective combining with a tube and an umbrella sheet, wherein the rod-shaped elements, the joint elements, the stretching elements and the retaining mechanism are all made integral in a single piece of plastic material constituting the foldable articulated arm.

The invention claimed is: 
     
       1. A foldable articulated arm comprising:
 a first rod-shaped element, a second rod-shaped element and a third rod-shaped element foldable one to another; 
 at least three stretching elements connected to the rod-shaped elements to form a system of four-bar linkages, 
 a plurality of joint elements connected to the rod-shaped elements and the stretching elements and having, at opposite ends, retaining means for a respective combining with a tube and an umbrella sheet, 
 wherein the rod-shaped elements, the joint elements, the stretching elements and the retaining means are together constructed of a single piece of plastic material constituting the foldable articulated arm; 
 wherein of the at least three stretching elements, a first stretching element has one free end and one opposite end hinged to the first rod-shaped element, a second stretching element has one end hinged to the first stretching element and one opposite end hinged to the second rod-shaped element and a third stretching element has one end hinged to the first rod-shaped element and one opposite end hinged to one end of the third rod-shaped element, and wherein the third stretching element comprises a flexible ribbon; 
 a runner slidable on the second rod-shaped element and constraining the flexible ribbon of the third stretching element to the second rod-shared element; 
 wherein the second stretching element comprises a flexible ribbon having one end combined with a back side of the second rod-shaped element and one end with the first stretching element. 
 
     
     
       2. The foldable articulated arm according to  claim 1 , wherein the runner is integral with said third stretching element. 
     
     
       3. The foldable articulated arm according to  claim 2 , wherein said runner comprises at least one right-angle folded lug jutting from an edge of said flexible ribbon. 
     
     
       4. The foldable articulated arm according to  claim 1 , further comprising a fourth stretching element having one end hinged to said first stretching element and one opposite end hinged to said second rod-shaped element, interposed between the first rod-shaped element and the second stretching element. 
     
     
       5. The foldable articulated arm according to  claim 1 , wherein each one of said joint elements make one hinged end of a respective rod-shaped or stretching element, essentially comprising one ending portion, of set limited length, of said respective rod-shaped or stretching element, having a reduced cross section with respect to a main body of the respective rod-shaped or stretching element, to be flexible or foldable. 
     
     
       6. The foldable articulated arm according to  claim 1 , wherein said retaining means comprise tooth-shaped ending portions of a free end of said first rod-shaped element, said third rod-shaped element and said first stretching element, which constitutes at least one chosen from a male component of a snap-fit coupling and, for said third rod-shaped element, an ending portion folded on itself. 
     
     
       7. The foldable articulated arm according to  claim 1 , wherein said main bodies of said rod-shaped elements and of said stretching elements are made of a first high density plastic material, and wherein at least one chosen from the joint elements and the retaining means are made of a second plastic material with density lower than said first plastic material. 
     
     
       8. An umbrella comprising a tube, a sheet and a plurality of foldable articulated arms according to  claim 1  constrained to said tube and said sheet at said retaining means. 
     
     
       9. The umbrella according to  claim 8 , wherein said tube is telescopic and it comprises at least three tubular elements, a first tubular element, to which the plurality of foldable articulated arms is combined, having a largest section among sections of said tubular elements. 
     
     
       10. The umbrella according to  claim 9 , wherein among said at least three tubular elements, a second tubular element is slidingly mounted inside said first tubular element, and is configured to slide between a first position in which it is substantially inside the first tubular element and a second position in which it is at least partially outside of the first tubular element, and a third tubular element slidingly mounted outside of said second tubular element and configured to slide between a position in which it is substantially inside the first tubular element and a position in which it is at least partially outside thereof and the second tubular element. 
     
     
       11. The umbrella according to  claim 10 , comprising a first and a second plurality of housing seats, the first plurality of housing seats positioned in the first tubular element, the second plurality of housing seats being positioned on at least one chosen from the second and third tubular elements, which form relative female components of the snap-fit coupling. 
     
     
       12. The umbrella according to  claim 11 , further comprising an annular element fitted onto said first tubular element and slidingly constrained thereto between a first position in which said articulated arms are closed and a second position in which said articulated arms are extended, said annular element comprising said second plurality of housing seats. 
     
     
       13. The umbrella according to  claim 12 , comprising stopping means of the travel of said annular element made in a single piece with said first tubular element. 
     
     
       14. The umbrella according to  claim 8 , comprising stopping means of the mutual travel of said tubular elements made integral with the tubular elements. 
     
     
       15. The umbrella according to  claim 8 , comprising threaded combining means arranged at an ending portion of said third tubular element, and a handle or base removably combined with said third tubular element at said threaded combining means. 
     
     
       16. The umbrella according to  claim 8 , further comprising a plurality of fastening elements, each one having a housing seat for a retaining element having the shape of a tooth of a third rod-shaped element of a respective foldable articulated arm, said sheet being fastened at relative apices to said plurality of fastening elements. 
     
     
       17. The umbrella according to  claim 8 , wherein said sheet is directly constrained at relative apices to said retaining means in the shape of folded ending portions of each one of said third rod-shaped elements. 
     
     
       18. The umbrella according to  claim 8 , wherein said sheet is a film of plastic material. 
     
     
       19. The umbrella according to  claim 8 , wherein said sheet is welded to at least one chosen from said plurality of foldable articulated arms and to said plurality of fastening elements. 
     
     
       20. The umbrella according to  claim 8 , wherein the entire umbrella is made of at least one chosen from recyclable and recycled plastic material.